Add RSS/Atom feed support for user actions (#16002)

Return rss/atom feed for user based on rss url suffix or Content-Type header.

vendor/github.com/gorilla/feeds/atom.go

@@ -0,0 +1,169 @@
+package feeds
+
+import (
+	"encoding/xml"
+	"fmt"
+	"net/url"
+	"time"
+)
+
+// Generates Atom feed as XML
+
+const ns = "http://www.w3.org/2005/Atom"
+
+type AtomPerson struct {
+	Name  string `xml:"name,omitempty"`
+	Uri   string `xml:"uri,omitempty"`
+	Email string `xml:"email,omitempty"`
+}
+
+type AtomSummary struct {
+	XMLName xml.Name `xml:"summary"`
+	Content string   `xml:",chardata"`
+	Type    string   `xml:"type,attr"`
+}
+
+type AtomContent struct {
+	XMLName xml.Name `xml:"content"`
+	Content string   `xml:",chardata"`
+	Type    string   `xml:"type,attr"`
+}
+
+type AtomAuthor struct {
+	XMLName xml.Name `xml:"author"`
+	AtomPerson
+}
+
+type AtomContributor struct {
+	XMLName xml.Name `xml:"contributor"`
+	AtomPerson
+}
+
+type AtomEntry struct {
+	XMLName     xml.Name `xml:"entry"`
+	Xmlns       string   `xml:"xmlns,attr,omitempty"`
+	Title       string   `xml:"title"`   // required
+	Updated     string   `xml:"updated"` // required
+	Id          string   `xml:"id"`      // required
+	Category    string   `xml:"category,omitempty"`
+	Content     *AtomContent
+	Rights      string `xml:"rights,omitempty"`
+	Source      string `xml:"source,omitempty"`
+	Published   string `xml:"published,omitempty"`
+	Contributor *AtomContributor
+	Links       []AtomLink   // required if no child 'content' elements
+	Summary     *AtomSummary // required if content has src or content is base64
+	Author      *AtomAuthor  // required if feed lacks an author
+}
+
+// Multiple links with different rel can coexist
+type AtomLink struct {
+	//Atom 1.0 <link rel="enclosure" type="audio/mpeg" title="MP3" href="http://www.example.org/myaudiofile.mp3" length="1234" />
+	XMLName xml.Name `xml:"link"`
+	Href    string   `xml:"href,attr"`
+	Rel     string   `xml:"rel,attr,omitempty"`
+	Type    string   `xml:"type,attr,omitempty"`
+	Length  string   `xml:"length,attr,omitempty"`
+}
+
+type AtomFeed struct {
+	XMLName     xml.Name `xml:"feed"`
+	Xmlns       string   `xml:"xmlns,attr"`
+	Title       string   `xml:"title"`   // required
+	Id          string   `xml:"id"`      // required
+	Updated     string   `xml:"updated"` // required
+	Category    string   `xml:"category,omitempty"`
+	Icon        string   `xml:"icon,omitempty"`
+	Logo        string   `xml:"logo,omitempty"`
+	Rights      string   `xml:"rights,omitempty"` // copyright used
+	Subtitle    string   `xml:"subtitle,omitempty"`
+	Link        *AtomLink
+	Author      *AtomAuthor `xml:"author,omitempty"`
+	Contributor *AtomContributor
+	Entries     []*AtomEntry `xml:"entry"`
+}
+
+type Atom struct {
+	*Feed
+}
+
+func newAtomEntry(i *Item) *AtomEntry {
+	id := i.Id
+	// assume the description is html
+	s := &AtomSummary{Content: i.Description, Type: "html"}
+
+	if len(id) == 0 {
+		// if there's no id set, try to create one, either from data or just a uuid
+		if len(i.Link.Href) > 0 && (!i.Created.IsZero() || !i.Updated.IsZero()) {
+			dateStr := anyTimeFormat("2006-01-02", i.Updated, i.Created)
+			host, path := i.Link.Href, "/invalid.html"
+			if url, err := url.Parse(i.Link.Href); err == nil {
+				host, path = url.Host, url.Path
+			}
+			id = fmt.Sprintf("tag:%s,%s:%s", host, dateStr, path)
+		} else {
+			id = "urn:uuid:" + NewUUID().String()
+		}
+	}
+	var name, email string
+	if i.Author != nil {
+		name, email = i.Author.Name, i.Author.Email
+	}
+
+	link_rel := i.Link.Rel
+	if link_rel == "" {
+		link_rel = "alternate"
+	}
+	x := &AtomEntry{
+		Title:   i.Title,
+		Links:   []AtomLink{{Href: i.Link.Href, Rel: link_rel, Type: i.Link.Type}},
+		Id:      id,
+		Updated: anyTimeFormat(time.RFC3339, i.Updated, i.Created),
+		Summary: s,
+	}
+
+	// if there's a content, assume it's html
+	if len(i.Content) > 0 {
+		x.Content = &AtomContent{Content: i.Content, Type: "html"}
+	}
+
+	if i.Enclosure != nil && link_rel != "enclosure" {
+		x.Links = append(x.Links, AtomLink{Href: i.Enclosure.Url, Rel: "enclosure", Type: i.Enclosure.Type, Length: i.Enclosure.Length})
+	}
+
+	if len(name) > 0 || len(email) > 0 {
+		x.Author = &AtomAuthor{AtomPerson: AtomPerson{Name: name, Email: email}}
+	}
+	return x
+}
+
+// create a new AtomFeed with a generic Feed struct's data
+func (a *Atom) AtomFeed() *AtomFeed {
+	updated := anyTimeFormat(time.RFC3339, a.Updated, a.Created)
+	feed := &AtomFeed{
+		Xmlns:    ns,
+		Title:    a.Title,
+		Link:     &AtomLink{Href: a.Link.Href, Rel: a.Link.Rel},
+		Subtitle: a.Description,
+		Id:       a.Link.Href,
+		Updated:  updated,
+		Rights:   a.Copyright,
+	}
+	if a.Author != nil {
+		feed.Author = &AtomAuthor{AtomPerson: AtomPerson{Name: a.Author.Name, Email: a.Author.Email}}
+	}
+	for _, e := range a.Items {
+		feed.Entries = append(feed.Entries, newAtomEntry(e))
+	}
+	return feed
+}
+
+// FeedXml returns an XML-Ready object for an Atom object
+func (a *Atom) FeedXml() interface{} {
+	return a.AtomFeed()
+}
+
+// FeedXml returns an XML-ready object for an AtomFeed object
+func (a *AtomFeed) FeedXml() interface{} {
+	return a
+}